org.geotools.data.crs.ReprojectFeatureIterator Maven / Gradle / Ivy

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/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2003-2008, Open Source Geospatial Foundation (OSGeo)
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation;
 *    version 2.1 of the License.
 *
 *    This library is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *    Lesser General Public License for more details.
 */
package org.geotools.data.crs;

import java.util.Iterator;
import java.util.NoSuchElementException;
import org.geotools.data.simple.SimpleFeatureIterator;
import org.geotools.feature.FeatureIterator;
import org.geotools.feature.simple.SimpleFeatureBuilder;
import org.geotools.geometry.jts.GeometryCoordinateSequenceTransformer;
import org.locationtech.jts.geom.Geometry;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.referencing.operation.MathTransform;
import org.opengis.referencing.operation.TransformException;

/**
 * ReprojectFeatureReader provides a reprojection for FeatureTypes.
 *
 * ReprojectFeatureReader is a wrapper used to reproject GeometryAttributes to a user supplied
 * CoordinateReferenceSystem from the original CoordinateReferenceSystem supplied by the original
 * FeatureReader.
 *
 * 
Example Use:
 *
 * 

 * ReprojectFeatureReader reader =
 *     new ReprojectFeatureReader( originalReader, reprojectCS );
 *
 * CoordinateReferenceSystem originalCS =
 *     originalReader.getFeatureType().getDefaultGeometry().getCoordinateSystem();
 *
 * CoordinateReferenceSystem newCS =
 *     reader.getFeatureType().getDefaultGeometry().getCoordinateSystem();
 *
 * assertEquals( reprojectCS, newCS );
 * 
 *
 * TODO: handle the case where there is more than one geometry and the other geometries have a
 * different CS than the default geometry
 *
 * @author jgarnett, Refractions Research, Inc.
 * @author aaime
 * @author $Author: jive $ (last modification)
 * @version $Id$
 */
public class ReprojectFeatureIterator implements Iterator, SimpleFeatureIterator {
    FeatureIterator reader;
    SimpleFeatureType schema;
    GeometryCoordinateSequenceTransformer transformer = new GeometryCoordinateSequenceTransformer();

    public ReprojectFeatureIterator(
            FeatureIterator reader,
            SimpleFeatureType schema,
            MathTransform transform) {
        this.reader = reader;
        this.schema = schema;
        transformer.setMathTransform(transform);

        // set hte target coordinate system
        transformer.setCoordinateReferenceSystem(schema.getCoordinateReferenceSystem());
    }

    /**
     * Implement getFeatureType.
     *
     * Description ...
     *
     * @see org.geotools.data.FeatureReader#getFeatureType()
     */
    public SimpleFeatureType getFeatureType() {
        if (schema == null) {
            throw new IllegalStateException("Reader has already been closed");
        }

        return schema;
    }

    /**
     * Implement next.
     *
     * 
Description ...
     *
     * @see org.geotools.data.FeatureReader#next()
     */
    public SimpleFeature next() throws NoSuchElementException {
        if (reader == null) {
            throw new IllegalStateException("Reader has already been closed");
        }

        // grab the next feature
        SimpleFeature next = reader.next();

        Object[] attributes = next.getAttributes().toArray();

        try {
            for (int i = 0; i < attributes.length; i++) {
                if (attributes[i] instanceof Geometry) {
                    attributes[i] = transformer.transform((Geometry) attributes[i]);
                }
            }
        } catch (TransformException e) {
            throw (IllegalStateException)
                    new IllegalStateException(
                                    "A transformation exception occurred while reprojecting data on the fly")
                            .initCause(e);
        }

        return SimpleFeatureBuilder.build(schema, attributes, next.getID());
    }

    public void remove() {
        throw new UnsupportedOperationException("On the fly reprojection disables remove");
    }
    /**
     * Implement hasNext.
     *
     * 
Description ...
     *
     * @see org.geotools.data.FeatureReader#hasNext()
     */
    public boolean hasNext() {
        if (reader == null) {
            throw new IllegalStateException("Reader has already been closed");
        }

        return reader.hasNext();
    }

    /**
     * Implement close.
     *
     * Description ...
     *
     * @see org.geotools.data.FeatureReader#close()
     */
    public void close() {
        if (reader == null) {
            return;
        }
        reader.close();
        reader = null;
        schema = null;
    }
}